1. Field of the Invention
The present invention relates to the field of vehicle maintenance, and more specifically, to servicing vehicle cooling fluid systems.
2. Description of Related Art
The engine cooling system is but one vehicle system that requires routine maintenance to extend the longevity of the system and the vehicle. A typical engine cooling system includes a radiator connected to a water pump via an effluent line which is in turn connected to a heater core and an engine block. An influent line completes the fluid loop by connecting the radiator inlet port to the outlet port of the engine block. Depending on the direction the water is pumped, this loop may be reversed. The radiator also includes a radiator pressure cap coupled to an overflow bottle via an overflow conduit.
Typically, as coolant evaporates or breaks down over time, a relatively simple maintenance routine involves the periodic monitoring of the radiator fluid level by visually examining the fluid level in relation to a fill line on the overflow bottle connected to the radiator. If the level is low, the bottle may be refilled with water, anti-freeze, or a pre-mix fluid by removing the cap to the overflow bottle and pouring in the desired fluid until the level is again at the fill line. Related to this, when the engine is sufficiently cooled, the fluid level in the radiator itself may be checked by removing the radiator cap to visually check the level of fluid in the radiator. The fluid may be topped off by pouring the proper fluid directly into the radiator through its fill neck.
As the efficiency of heat transfer deteriorates with time, as from broken down aged coolant, the risk of overheating and damaging the engine is increased. Thus, in addition to these routine topping off procedures, most dealers or service technicians recommend changing the engine coolant completely every 15,000 to 20,000 miles. Of course, this may vary depending on the vehicle. In the interim, it may also be advisable to exchange a significant amount of fluid to maintain the vehicle in top form and extend the life of the vehicle. Thus, in some instances, it may be necessary to exchange some or all of the old fluid in the radiator with new fluid or flush the radiator completely.
One early method of replacing old coolant required the service technician to disconnect the lower effluent hose from the bottom of the radiator and allow the free end to drain into a collection tank. Then it was a matter of routine for the technician to insert a flushing hose into the fill neck of the radiator to flush the system until the fluid exiting the bottom of the radiator ran clear. Often, the fluid was drained directly into the street drain or public sewage system leading to undesirable environmental impacts. Once the flushing was accomplished the lower hose was reconnected and the radiator refilled with the recommend type of anti-freeze and water or a pre-mix until the fill line in the radiator was reached. The overflow bottle was then also filled. However, this fluid replacement method wasted a considerable amount of water to completely flush the radiator. In addition, this procedure, being dependent on the pressure of the flushing hose and gravity fluid flow, took a considerable amount of time to flush the contents of the radiator and did not result in satisfactorily flushing the entire cooling system.
To improve the speed of these fluid exchange procedures, a number of machines were developed to remove and replace the coolant within the radiator. Such machines introduced pump assisted fill or drain procedures to force fluid through the vehicle's engine cooling system but with the engine running so the thermostat remained open. One such exemplary machine may be found in U.S. Pat. No. 5,853,068 to Dixon et al. This machine includes a single pump used to draw fluid from a fresh fluid reservoir into the engine cooling system while the vehicle engine is running and the water pump is forcing old fluid out of the engine cooling system into a waste collection tank. An overpressure switch is responsive to pressure build-up beyond pre-set tolerable limits, such as from a defective thermostat. However, such system has a drawback as a significant amount of new fluid must be introduced into the system to ensure the air is completely forced out of the engine coolant loop.
Another example of prior efforts is found in U.S. Pat. No. 5,390,636 to Baylor et al. This type of machine uses compressed air to force supply fluid into the engine cooling system to displace the old fluid. However, residual amounts of compressed air often become trapped the engine cooling system. In recognition of this problem a valve is closed in response to predetermined coolant level drop in a supply tank to relieve air pressurization of the tank and interrupting coolant flow. Thus, the system is controlled by deactivating air flow based on a measured quantity of coolant fluid delivered from the supply tank. Either a low level float in the supply tank or a relay connected to a solenoid is responsive to close a valve when a low level switch triggers the relay to cease introduction of additional pressurized air. However, a failure in the switching system or valve closure would result in introducing air into the engine coolant system. Also, according to this patent, the air is bled from the system if necessary, indicating that some air may be trapped during the process.
The problem with leaving air in the vehicle cooling system is that a dangerous condition can arise if too much air remains. Air in the system can expand when heated and blow the hoses or otherwise weaken the hoses thereby shortening the lifespan of the cooling system of the vehicle. In addition, during this procedure, the engine is also running to maintain the thermostats in an open state requiring the service technician to perform additional safety procedures.
What is needed and heretofore unavailable is a radiator fluid exchanging apparatus configured to perform a variety of servicing procedures including an interim exchange using vacuum assisted fluid control and complete exchange with the engine in an off condition along with providing the versatility of collecting fluid for waste control purposes while reducing the likelihood of introducing air into the vehicle cooling system.